Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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2147870
L1YLJC~C~7C~171~~~.f
MAKING TEXTILE STRANDS
This invention relates to making textile strands.
EP-A-0 0'.37 118 describes methods for making a
bulky flat yarn comprising preparing at least two kinds
of thermoplastic synthetic undrawn yarns having
different natural draw ratios, simultaneously drawing
these prepared yarns at a draw ratio which is equal to
or larger than the smallest natural draw ratio of the
yarns and releasing drawing tension in the yarns after
they are drawn. The yarns are mixed by means of an
interlacing nozz:~Le before or after they are drawn.
These operations,, utilising differences in the elastic
recovery of the constituent yarns rather than their
shrinkage properl~ies, produce a filament yarn having
high bulk and resiliency, without any crimps.
In the article "Lufttexturierung: Produkte and
Technologie" (Air texturing: Products and Technology),
E. Kreuzer; Chemiefasern/Textilindustrie 35, 87 Jahrgang,
October 1985, pa<~es 674 to 678 the texturizing machine
FK6T-80 is described, and the possibilities for
arranging the machine components to perform different
texturing operat:LOns explained.
AMEND~p SHEET
2~~7870
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EP-0 057 583 discloses a method for making a
textile strand involving differentially overfeeding two
separate filament.ous strands to a jet device which
commingles and interlaces and forms loops in the
filaments of the strands and then subjecting the
commingled strand. to.a heating step in which loops
formed by the jet. are pulled out and in so doing tighten
any entanglements present as a result of the jet
treatment and thus consolidate the strand. A
"twistless" sewing thread can be produced in this way,
"twistless" implying not that the thread is without
twist, because twist can always be added, but rather
that the thread h.as been produced without the need for
twisting which is implicit in the production of sewing
thread from staple fibre such.as cotton.
The method of EP-0 057 583 is capable of
modification to vary the properties of the strand
produced and, especially when sewing thread is being
produced, can be adapted to produce a more or less
"loopy" thread. It is sometimes suggested that the
presence of loops in the thread can assist cooling of a
sewing machine needle.
AMENDED SHEET
WO 94/10362 ~, ~ ~ PCT/GB93/022: ~~
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All modifications which have been suggested to
the fundamental methods of EP-0 057 583 have, however,
not resulted in a more economical production of a sewing
thread, nor, indeed, could any more economical production
be envisioned, since the method itself eliminates the
major cost component of the production of conventional
sewing thread, namely the twisting step or steps
involved in consolidating the staple fibres into a
coherent yarn.
The present invention provides methods for
making a textile strand which, while maintaining the
flexibility of the method of EP-0 057 583 for the
production of different specifications of strand,
especially in the context of sewing thread, gives, at
the same time, th.e possibility o.f substantial cost
reductions in the process.
The invention comprises a method for making a
textile strand comprising passing two filamentous
strands together through a jet device which commingles
filaments of the two strands and then subjecting the
thus commingled strands to a drawing step in which at
least one of the strands is drawn to a stable drawn
state.
The strands may be dissimilar.
WO 94/10362 ~ 1 ~ g "~ o PCT/GB93/02256
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The strands may be dissimilar in the extent to
which they can be drawn. They may be partially drawn
before the jet, and they may have been differentially
overfed to the jet.
One strand may be overfed to the jet. Typical
overfeeds may be 40~ to 60~, but smaller and larger
overfeeds may be useful in different circumstances.
The strands may be of the same polymer material,
and will usually be multifilament: strands, but three or
more strands may :be used, and one such may be a mono-
filament or a law filament count strand. Staple fibre
strand may also be incorporated.
The commingled, drawn strand may be subjected to
a heating step - 'the heating step may be at a temperature
at which shrinkaga_ (or more shrinkage) would take place
were the strand not held to length or permitted to
contract by only a limited amount. A higher temperature
may be employed to yield higher tenacity in the finished
thread.
The invention also comprises a textile strand
made by a process as disclosed, and such strand may
comprise a sewing thread.
CA 02147870 2003-05-12
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According to a first aspect of the invention, there is provided a
method for making a coherent twist-free or low-twist strand by over feeding
two
filamentous strands together through a jet device which commingles filaments
of
the two strands and forms loops therein, the two strands being drawable, and
the
commingled strand being treated after the jet, characterized in that the
strands
before entering the jet are not drawn or are incompletely drawn and that after
leaving the jet the treatment of the commingled strands completes the drawing
process and consolidation of the strand is effected or assisted by tightening
brought about by the jet and the treatment after the jet.
According to a second aspect of the invention, there is provided a
textile strand comprising a coherent twist-free or low-twist strand made by
over
feeding two filamentous strands together through a jet device which commingles
filaments of the two strands and forms loops therein, the two strands being
drawable, and the commingled strand being treated after the jet, characterized
in
that the strands before entering the jet are not drawn or are incompletely
drawn
and that after leaving the jet the treatment of the commingled strands
completes
the drawing process and consolidation of the strand is effected or assisted by
tightening brought about by the jet and the treatment after the jet.
W094/10362 ~~$~~ PCT/GB93/022~
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Methods for making textile strands according to
the invention will now be described with reference to
the accompanying drawings, in which .
Figure 1 is a diagrammatic illustration of one
method;
Figure 2 is a diagrammatic illustration of
another method;
and Figure 3 is a diagrammatic illustration of yet
another method.
The methods illustrated in Figures 1 and 2
comprise passing two dissimilar filamentous strands
11,12 together through a jet device 13 which commingles
and forms loops in the filaments of the two strands
11,12 and then subjecting the thus commingled strands to
a drawing step 14 in which at least one of the strands
is drawn to a stable drawn state.
By "stable drawn state" is meant a state in
which, at the temperature at which a Finished product
will be used - in the case of ordinary textile strands,
such for example as those used as sewing threads, this
will~of course be room temperature and probably extend
up to normal laundering, cleaning and pressing
2147870
WO 94/ 10362 PCT/G B93/02255
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temperatures - the strand will extend under tension
elastically, at least initially, rather than
inelastically (with plastic or drawing extension).
If the strands are of different weights, one,
perhaps, constitui;..ing a core or load-bearing strand, the
other being an ef:Eect or binding strand - it will
usually be preferred that the heavier or core strand is
drawn to the stable drawn state.
The strands 11,12 may be dissimilar in the
extent to which they can be drawn.
Figure 1 illustrates a method in which strands
11,12 start out (or at least may start out) as similar
strands supplied on packages 111,121, both, perhaps,
being of POY. The two strands as supplied from packages
111,121 are drawn by differential speed godets 112,113;
122,123. The draw ratios achieved by godet pairs 112,
113;122,123 may each be substantially less than the full
extent to which it: is possible to draw the strands.
Strand 11 may be drawn with a ratio 1.84:1, strand 12
with a ratio 1.78:1. Godet 123 may be arranged to
rotate faster, by, say, 40~ or 60'~ or even more, than
godet 113 so as to overfeed strand 12 to the jet 13, by
more than strand 11. is overfed thereto. The commingled
strand is further drawn in the drawing stage 14 at a
ratio 1.27:1.
21478'0
WO 94/10362 PC1'/GB93/022.°
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The drawing stage 14 comprises input godet 141,
and output hot godet 142. The drawn strand from godet
142 is then overfed 21/2- 4~ to a further godet
15. The thus hot relaxed strand is wound up.
In the method of EP-0 057 583 the speed at which
the strand is wound up depends upon the rate at which
the jet can handle the strands. In the present method,
the strands are subject to a further drawing stage after
the jet. In the method of Figure 1 this drawing stage
is carried out at a draw ratio of 1.27:1. The finished
strand is thus wound up some 27~ faster than is possible
in the method as described in EP-0 057 583.
Figure 2 illustrates a method in which dissimilar
starting materials are used as strands 11,12, supplied
from packages 211,221 and fed together to a drawing
stage between godets 202,203. The strands 11,12 are
dissimilar at least in regard to the extent to which
they can be drawn. The partially drawn strand
combination 11,12 is overfed to the jet 13 where the
filaments of the strands 11,12 are commingled.
The commingled strand is drawn. in the drawing
stage 14 and when it leaves that stage the filaments
contributed by strands 11,12 will have differential
shrinkage because one of the strands will have been
WO 94/10362
214 7 ~ ~ 0 PCf/GB93/02255
drawn to a lesser proportion of its possible draw ratio
than the other. The drawn strand from the drawing stage
14 comprising input and output godets 141,143 is
subjected to a heating step by plate heater 215 while
being held to length or allowed to have controlled
shrinkage (or even, perhaps, stretched a little more) by
a further godet roll 216 from where it is forwarded to a
wind-up package 1.7.
Figure 3 illustrates a method generally like
that illustrated in Figure 1 but in which no drawing
takes place before the jet. Strands 11 and 12 both of
POY but with strand 11 used as an effect yarn of lower
dtex than strand 12 are overfed to a drawing stage 14 by
feed rollers 113,123. Feed rollE~r 113, as before,
ovErfeeds by 40~ (or more or less) with respect to the
first-encountered roller 141 of the drawing stage 14,
while feed roller 123 overfeeds by, say, 4.5$ relative
to that same roller 141. The commingled strands from
the jet 13 are then drawn to the normal extent to which
such yarns are hot drawn, or even ove=drawn, in the
drawing stage 14 and subsequently subjected to hot
relaxation between the hot godet 142 and a godet 15 as
before.
It will be noted that in the method of Figure 1,
the wind-up arrangement 18 is overend, as by a ring and
WO 94/10~~ ~ ~ ~ ~ O PCT/GB93/0225
_ g _
traveller, while in Figures 2 and 3 a side wind-up 17 is
illustrated. The thread wound up in the method of
Figure 1 will have some twist inserted during winding.
Twist may be desirable for certain end uses, although
for sewing thread, for example, the amount of twist
which may be inserted to improve the sewing properties
over the thread as produced without twist will be very
substantially less than the twist required to make
thread from staple fibres. The cost of manufacture of
sewing thread can then be very much reduced by processes
according to the present invention where twist is not
required, or is not required to anything like the same
extent.
When a side wind-up is used, any desired amount
of twist may be inserted in a subsequent operation.
Consolidation of the thread is effected, or at
least assisted, by the commingling effect of the jet 13
and the subsequent tightening brought about by the
processes after the jet.
The methods described are particularly
advantageous over other methods of producing coherent
twist-free or low-twist strands in which drawing is
effected completely before a jet commingling device
inasmuch as the throughput of such methods is limited by
WO 94/10362 214 7 g 7 ~ PCT/GB93/02255
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the jet. With the present methods, a substantial
proportion or indeed all of the draw is effected after
the jet and this in effect means that the strand is
produced correspondingly faster.
On the other hand, even delaying a small
proportion of the' draw until after commingling in the
jet can have beneficial effects, producing a finer
strand which has a higher tenacity (by as much as 10~)
than if a1.1 the drawing is effected before the jet. At
the same time any tendency to individual filament
breakage on drawing before the jet is reduced and the
resulting strand is noticeably smoother.
Many variations can be played on the basic
method as defined. above and described with reference to
the drawings. For example, hot drawpin or a plate
heater may be used for hot drawing instead of the hot
roller as described; cold drawing may be appropriate in
some circumstances.
And the possibility of filament breakage may
itself be turned to good effect by inducing filament
breakage after the jet to produce a thread with
controlled filament breakage which would more resemble a
spun thread.
